I would guess because he's trying to troubleshoot his rifle. Also, he may not be so much interested in knowing how his rifle will group a 5 or 10 shot string as the barrel heats up, as he is in knowing where his first shots from his hunting rifle hit with a cool barrel on the first shots. Ideally a gun wouldn't move point of impact from cool barrel to a heated barrel. But the thinner tubed versions often do start to enlarge the groups as they heat up. So I also cool my gun barrel down in the effort to learn how well the gun will group with a developed load with a cool barrel, rather than a barrel that starts out cool and ends up at 100F. In fact when there's snow outside I'll grab a handful and run it along the outside of the barrel from the forend on out to the muzzle to reduce the length of time I'm twittling my thumbs waiting for the barrel to cool down.Why are you going to cool down your rifle to check you first cold-bore shot?
If the first shot from a cold bore's not where the rest of them go, there's something not quite right with your rifle. Through 600 yards, the first shot from a cold bore should be within 1/3rd MOA of where 5 to 20 or more shots center up afterwords.
Nightforce has great tracking capabilities, they are rugged, a bunch of elevation, holds zero forever, and reticles are designed for long range shooting. So if you are looking to shoot long distances constantly, then you need a scope that can take the abuse. -- gilmillan1
Nightforce is such a solid combo of reticle, available elevation, glass that is good enough to shoot at the longest range you can dial. Nightforce has bullet proof construction that can handle the incidental horse rolling or some other rodeo action. -- bigngreen
The total package. Nightforce is the best I have used as far as turret feel and solid detents. I have never had one that didn't track right on and always return to zero. Nightforce NXS is the best value for everything I need. -- Broz